docs: def get_peak_mem():
      '''
      this returns peak memory use since process starts till the moment its called
      '''
      import resource
      rusage_denom = 1024.
      if sys.platform == 'darwin':
          # ... it seems that in OSX the output is different units ...
          rusage_denom = rusage_denom * rusage_denom
      mem = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss / rusage_denom
      return mem